Addenbrooke's Hospital in Cambridge is the latest to declare a major incident due "extreme pressure" on its A&E services.
Cambridge University Hospitals (CUH) said it had cancelled all non-emergency surgery and procedures at the hospital and urged patients not to attend the A&E unit unless they have an emergency or life threatening condition.
In a statement, CUH said it had been under extreme pressure since New Year's Eve and had been "in critical internal incident mode" for the last two days.
"This is due to unprecedented levels of demand on our services with especially high numbers of frail elderly patients, combined with a record level of patients whose medical care is finished and whose discharge is delayed.
“Our priority is to care safely for the patients already in the hospital and arrange the safe discharge of those who are well enough to go home and to ensure that we can provide care for those who require urgent treatment," it said.
Ed Miliband wants former nursing staff to be drafted in as part of a new five-point plan to ease the burden on accident and emergency.
Hospitals are saying there simply are not enough beds and trained medical staff for sick patients who need to be admitted.
With A&E waiting times slumping to their worst in 10 years, did your hospital make it on to the worst 10 list?